<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        let week = prompt('请输入星期几')
        switch (week) {
            case '星期一':
                document.write('monday');
                break
            case '星期二':
                document.write('tuesday');
                break
            case '星期三':
                document.write('wednesday');
                break
            case '星期四':
                document.write('thursday');
                break
            case '星期五':
                document.write('friday');
                break
            case '星期六':
                document.write('saturday');
                break
            case '星期日':
                document.write('Sunday');
                break
            default:
                document.write('没有定义');
        }
    </script>
</body>

</html>